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Force and Motion - Grades 3-5

Nebraska Science Standards
5.2.2.a Describe motion by tracing and measuring an object’s position over a period of time (speed)

5.2.2.b Describe changes in motion due to outside forces (push, pull, gravity)

Objective: Students will identify the influence of forces on motion and describe motion by tracing and measuring an object's position over a period of time (speed). Students will be able to describe changes in motion due to outside forces (push, pull, gravity) and be able to describe magnetic behavior in terms of attraction and repulsion.

Materials:

Provided by Student:

  • Large bottle cap

 

Provided by CSM

  • Craft Sticks
  • Pom Poms
  • Rubber Bands
  • Glue gun (to be used by the volunteers not the children)
  • Glue sticks

 

Discussion:

What is force?

  • Force is the movement of an object as a result of interaction from another object. Whenever there is an interaction between two objects, there is a force upon each of the other objects

 

What are some examples of a force?

  • Push, pull, gravity
  • Discuss what gravity is
    • Gravity is a force that for us is always directed downwards. But to say that gravity acts downwards is not correct. Gravity acts down, no matter where you stand on the Earth. (It is better to say that on Earth gravity pulls objects towards the centre of the Earth. So no matter where you are on Earth all objects fall to the ground)

Earth

What is motion?

  • Motion is just another way of saying movement. Each type of motion is controlled by a different type of force

 

What is speed?

  • Speed is the total distance traveled divided by the total time it took to travel that particular distance
  • Speed is dependent on the amount of time that it takes a person or object to move toward something

 

How does motion change with force?

  • If a force acts on an object it will change either its speed, direction or both. This is Newton’s 2nd Law of Motion
  • Think if you have a basketball and it goes rolling into the street and gets hit by a bike -- the ball will change its direction or its speed or both. The same is true for the bike.
    • In this example the ball is the object, the bike is the force, the motion depends on the presence of the bike and will either continue on its path or change paths depending on where the bike hit it

 

Activity:

Building a catapult

Part of the fun of STEM projects is solving a challenge through trial and error. Allow the children to engineer the catapult on their own at first, but remember this is supposed to be fun so if it is too challenging/frustrating for the children go around and help each group by suggesting solutions and asking for predictions. (“Do you think it will work if we do this? Why or why not?)

Provide each child with 7 sticks and 5 rubber bands. They can work as teams or individuals (ask the teacher what is best for this particular class)

Procedure

  1. Using the glue gun, secure the lid onto the very tip of a stick. Allow to dry. This serves as the bucket for holding and launching various items and will be the stick on top (As shown below)
  2. Stack 5 craft sticks on top of each other and fasten them together tightly with a rubber band on the end like shown below.
  3. Fasten the opposite side with another rubber band, tightly securing the craft sticks together.
  4. Grab 2 more craft sticks and fasten those together with a rubber band creating a V like shape with the “bucket” stick on top
  5. Place the craft sticks from step 2 in between the craft sticks from step 4 (like shown below); this will provide support for the catapult.
  6. Secure the two parts together with rubber bands in the middle where the sticks meet. Again make sure the rubber bands are tightly secured.
  7. Place poms poms into the lid. Use one hand to hold the bottom of the catapult down while using 1 finger from your other hand to gently pull back on the lid and release to launch the pom poms into the air!

 

Catapult